1. Field of the Invention
The present invention relates to firearm sights and, more specifically, to a method and apparatus for removably attaching a mount for an optical or telescopic sight to a rifle.
2. Discussion of the Prior Art
Military and competition shooters have come to appreciate the simple construction and reliable operation of rifles having Garand-style rolling block operation. Such Rifles include the M1 Garand (in 30-06 caliber), the M1A (in .308 or 7.62 NATO caliber) and the select fire M14 (also in .308 or 7.62 NATO caliber).
The M14 is still used for certain military applications, in part because of the significant power advantage provided by the .308 or 7.62 NATO caliber projectiles, when compared to the standard issue .223 or 5.56 NATO caliber projectiles used in the M16 rifle or M4 carbine. Unfortunately, many of the modern M16/M4 attachments and accessories are not readily used with an M1A or M14 pattern rifle, since those rifles were originally configured for use solely with iron or mechanical sights. When special circumstances (e.g., a need for sniper rifles) mandated mounts for telescopic sights, armorers could not simply screw traditional sporting or Weaver™ style rails above the M1 Garand's rolling-block action receiver.
Armorers eventually developed mounts for use with optically sighted M1s; the first version was known as the M1C and utilized a telescopic sight held in place by a commercial (Griffin and Howe) “rail system” mount having a mounting method devised to avoid drilling and tapping the receiver and using a barrel collar which accepted a scope mount that attached utilizing a knurled knob on the mounting collar. The rail system (or lever) telescope mount required that the receivers be shipped to Griffin and Howe to drill and tap the receiver before heat-treating. The heat treating process associated with drilling and tapping the receiver (for the Griffin and Howe system) delayed production and so few M1Cs were delivered for combat service during W.W.II. In an effort to avoid the heat treatment problems associated with drilling and tapping the M1 receivers, a second approach to scope mounting utilized a machine base fitted to the rear of the barrel with a pin. The scope was releasably mounted to the barrel base with a knurled screw tightened by hand. This approach avoided the necessity of heat treatment after drilling and tapping. These expensive and protracted procedures resulted in a telescopic mount of acceptable but not superior accuracy. When the M1A and M14 replaced the M1 Garand as the principal service rifle, many of the same mounting problems were also carried forward, since the newer rifles also used the rolling block action and receiver configuration.
This legacy now creates a number of new problems for armorers. Contemporary users of the M14 and M1A have sought to use modern optical sighting systems including, for example, the Trijicon ACOG (i.e., “Advanced Combat Optical Gunsight”) optical sighting system, but there is not a practical way to releasably mount such modern optical devices to these older service rifles. The ACOG uses both tritium and fiber optic technology to illuminate a red circle reticle covering four minutes-of-angle (MOA), with a hollow center that covers 2 MOA. The ACOG sight is in use around the world by U.S. and coalition forces, and has been found to be very effective and rugged. The ACOG provides a relatively short one and one-half inches of eye relief and an eight millimeter exit pupil. Weighing about three-quarters of a pound with a flattop mount, the ACOG is compact and relatively light, while offering the durability needed in a combat sight. It offers much greater hit probability for most shooters, and is considered a lifesaver in low light combat situations. As a result, soldiers and marines have become accustomed to using the ACOG and similar optical devices on their service weapons.
There is a need, therefore, for a practical method and mount structure permitting a shooter to releasably mount modern optical devices to older service rifles, if they are to be used in combat.